A Study of JNJ-78278343 in Combination With JNJ-95298177 for Treatment of Prostate Cancer

NCT07082920 | Recruiting Phase 1 FDA Drug

• 1 other identifier: 78278343PBPCR1004
• Study Type: interventional
• Target: 140
• Locations: 2 countries
• Sites: 6

Brief Summary

The purpose of this study is to identify the recommended phase 2 combination dose (RP2CD) of JNJ-78278343 in combination with JNJ-95298177 in Part 1 (Dose confirmation) of the study and to determine how safe and tolerable the RP2CD is for treatment of participants with metastatic castration-resistant prostate cancer (mCRPC; a stage of prostate cancer where the cancer has spread beyond the prostate and is resistant to hormonal therapy) in Part 2 (Dose expansion) of study.

Conditions

Prostatic Neoplasms

Outcome Measures

Primary Outcomes (2)

• Number of Participants With Adverse Events (AEs) by Severity

  An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Severity will be graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0. Severity scale ranges from Grade 1 (Mild) to Grade 5 (Death). Grade 1= Mild, Grade 2= Moderate, Grade 3= Severe, Grade 4= Life-threatening and Grade 5= Death related to adverse event. Cytokine release syndrome (CRS) and immune effector cell associated neurotoxicity syndrome (ICANS) will be graded according to the American Society for Transplantation and Cellular Therapy (ASTCT) guidelines and ocular events will be graded using the alternative scale provided in the protocol.

  Up to 2 years 2 months

• Part 1: Number of Participants With Dose-Limiting Toxicity (DLT)

  High grade hematologic or non-hematologic toxicities with exceptions and/or toxicities leading to treatment discontinuation will be regarded as DLT.

  Up To Day 22

Secondary Outcomes (9)

• Objective Response Rate (ORR)

  Up to 2 years 2 months

• Prostate-Specific Antigen (PSA) Response Rate

  Up to 2 years 2 months

• Radiographic Progression-Free Survival (rPFS)

  Up to 2 years 2 months

• Time to Response (TTR)

  Up to 2 years 2 months

• Duration of Response (DOR)

  Up to 2 years 2 months

Study Arms (2)

Part 1: Dose Confirmation

EXPERIMENTAL

Participants will receive JNJ-78278343 in combination with JNJ-95298177 in a dose de-escalation schedule in accordance with the Bayesian Optimal Interval Design (BOIN) design to determine the recommended phase 2 combination dose (RP2CD) regimen.

Drug: JNJ-78278343; Drug: JNJ-95298177

Part 2: Dose Expansion

EXPERIMENTAL

Participants will receive JNJ-78278343 in combination with JNJ-95298177 at the RP2CD as determined in Part 1 of the study to confirm the safety and anti-tumor activity.

Drug: JNJ-78278343; Drug: JNJ-95298177

Interventions

JNJ-78278343 DRUG

JNJ-78278343 will be administered intravenously.

Also known as: Pasritamig

Part 1: Dose Confirmation; Part 2: Dose Expansion

JNJ-95298177 DRUG

JNJ-95298177 will be administered intravenously.

Also known as: ARX517

Part 1: Dose Confirmation; Part 2: Dose Expansion

Eligibility Criteria

• Age: 18 Years+
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Histologically confirmed adenocarcinoma of the prostate. Primary small cell carcinoma, carcinoid tumor, neuroendocrine (NE) carcinoma, or large cell NE carcinoma arising in the prostate are not allowed; however, adenocarcinomas with NE features (for example \[e.g.\], immunohistochemistry \[IHC\] with both androgen receptor \[AR\]- and NE-marker positivity) are allowed
• Must have metastatic castration-resistant prostate cancer (mCRPC)
• PSA must measure at least 2 nanograms per milliliters (ng/mL) at screening
• Measurable or evaluable disease
• Prior orchiectomy or medical castration; or, for participants who have not undergone orchiectomy, must be receiving ongoing androgen deprivation therapy with a gonadotropin-releasing hormone (GnRH) analog (agonist or antagonist) prior to the first dose of study drug and must continue this therapy throughout the treatment phase
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

You may not qualify if:

• Toxicity related to prior anticancer therapy that has not returned to grade less than or equal to (\<=) 1 or baseline levels (except for alopecia and vitiligo)
• Known allergies, hypersensitivity, or intolerance to any of the components (e.g., excipients) of JNJ-78278343 or JNJ-95298177
• Participants with leptomeningeal disease or brain metastases, with the exception of participants with definitively, locally treated brain metastases that are clinically stable and asymptomatic greater than (\>) 2 weeks, and who are off corticosteroid treatment for at least 2 weeks prior to first dose of study treatment
• Treatment with any anti-cancer or investigational agents within 14 days prior to the first dose of study treatment; specific requirements for certain anti-cancer therapies are as follows:
• Any T-cell redirecting treatment (e.g., CD3-directed bispecific or Chimeric Antigen Receptor T-cell \[CAR-T\] therapy) within 90 days prior to the first dose of study treatment
• Immune checkpoint inhibitors within 6 weeks prior to the first dose of study treatment
• Radium (Ra) 223 dichloride within 28 days prior to the first dose of study treatment
• Any prior treatment with kallikrein-related peptidase 2 (KLK2)-targeted therapy
• Any prior prostate-specific membrane antigen (PSMA)-targeting therapy (that is \[i.e.\], participants who received PSMA-targeting radioconjugates are excluded) \[Parts 2A and 2B only\]. Prior PSMA RLT is allowed in Part 1 and required for Part 2C and Part 2D but last dose must be \>3 months prior to the first dose of study treatment
• Any prior antibody drug conjugates (ADCs) with microtubule inhibitor payloads (e.g., auristatins, maytansinoids, tubulysins)
• Any serious underlying medical conditions or other issue that would impair the ability of the participant to receive or tolerate the planned treatment at the investigational site to understand the informed consent, or any condition for which, in the opinion of the investigator, participation would not be in the best interest of the participant or that could prevent, limit, or confound the protocol-specified assessments

Sponsors & Collaborators

• Janssen Research & Development, LLC: lead

Study Sites (6)

Florida Cancer Specialists

Sarasota, Florida, 34232, United States

RECRUITING

Columbia University Medical Center

New York, New York, 10032, United States

RECRUITING

University Hospitals Cleveland Medical Center

Cleveland, Ohio, 44106, United States

RECRUITING

Fred Hutchinson Cancer Center

Seattle, Washington, 98109, United States

RECRUITING

The Christie Nhs Foundation Trust

Manchester, M20 4BX, United Kingdom

RECRUITING

Royal Marsden Hospital (Sutton)

Sutton, SM2 5PT, United Kingdom

RECRUITING

MeSH Terms

Conditions

Prostatic Neoplasms

Condition Hierarchy (Ancestors)

Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Prostatic Diseases; Male Urogenital Diseases

Study Officials

• Janssen Research & Development, LLC Clinical trial

  Janssen Research & Development, LLC

  STUDY DIRECTOR

Central Study Contacts

Study Contact

CONTACT

844-434-4210; Participate-In-This-Study1@its.jnj.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 22, 2025
• First Posted: July 24, 2025
• Study Start: July 7, 2025
• Primary Completion (Estimated): January 28, 2027
• Study Completion (Estimated): March 1, 2027
• Last Updated: April 13, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share

Locations

GB (2); US (4)